It is known to those skilled in the art that cumene can be oxidized to cumene hydroperoxide and that cumene hydroperoxide can be decomposed by various means to provide phenol and acetone.
In the past certain acid catalysts have been used for producing phenol and acetone. In the cases where acidic substances are utilized as the catalysts the yields are satisfactory, however many of these acid catalysts require substantial expenditure for production of phenol and acetone, there are disposal problems with spent acids or their salts, and there are difficulties in achieving &gt;99.9% purity phenol required by today's market place due to entrainment or breakthrough of said acids. In addition, by-products such as mesityl oxide, .alpha.-methylstyrene, acetophenone and 2-phenyl-2-propanol are produced along with the product and must somehow be removed and processed.
The use of clays in catalysis is also known.
In an article titled "Catalysis: Selective Developments", Chem. Systems Report 84-3, 239-249, at Section 3.4320, the unusual properties of smectite clays which make them of interest as catalysts are discussed. These compositions are layered and exhibit a 2:1 relationship between tetrahedral and octahedral sites. In addition, the combination of cation exchange, intercalation and the fact that the distance between layers can be adjusted provide interesting possibilities.
There is a discussion of clay mineral catalysts, including "acid" montmorillonite clay catalysts in "Progress in Inorganic Chemistry", Vol. 35, p. 41 (1987). The process of pillaring this type of catalyst is discussed. Pillaring can convert a clay lamellar solid into a more heat resistant two dimensional zeolite material.
U.K. patent application No. 2,179,563 (1987) discloses the use of modified, layered clay catalysts in reactions capable of catalysis by protons. The particular suitability of montmorillonite clays is discussed.
The use of stabilized pillared interlayered clays as catalysts in reactions capable of catalysis by protons is disclosed in European patent application 0,083,970.
In U.S. Pat. No. 4,665,044 to Pinnavaia, et al., modified clays containing 6.1 to 9.8 ferric ions per cell are prepared by contacting an aqueous slurry of layered lattice clay with a hydrolyzed solution of ferric ion.
In related U.S. Pat. No. 4,665,045 a catalyst is prepared which is similar to that of '044, but contains chromium ions.
In an article in J. Mol. Catal., 27 (1984) 195, Pinnavaia, et al. discuss the pillaring and delamination of smectite clay catalysts by polyoxocations of aluminum. The results of the work demonstrate that pore openings of pillared montmorillonite and montronite clays are determined principally by the method used to dry the flocculated reaction products.
In an article titled "Synthesis of Interlamelar Montmorillonitediphenylphosphine Triosmium Cluster Complexes" in Appl. Catal., 1987, 35, 177 Choudary et al. disclose that clays can be used as alternatives to polymers and inorganic oxides as supports for clusters.
In European patent application 0 250 168 a method is disclosed for production of glycol ethers by reacting an olefin oxide with an alkanol over a cation-exchangeable lamellar clay catalyst wherein the exchangeable cations of the catalyst are cations of one or more rare earth elements.
Gaaf, et al. discuss work showing that nickel substituted mica montmorillonite (Ni-SMM) clay can be intercalated successfully with aluminum and silica-alumina oligomers leading to pillared clays; transmission electron microscopy has revealed agglomeration of the particles which leads to suppression of hydroisomerization catalysis. See J. Chem. Soc. Chem. Comm., 655, 1983.
In J. Am. Chem. Soc., 1985 107, 4783, Pinnavaia et al. discuss properties of chromia pillared clay catalysts which exhibit gallery heights that are about 3.0 .ANG. larger than those of zirconia and alumina pillared clay catalysts.
There is a good overview of the use of pillared cation-exchanged and acid-heated montmorillonite catalysts in Applied Clay Science, 2, (1987), p. 309.
A catalytic application of smectite clays is discussed in an article titled "Catalysis of Friedel-Craftrs, Alkylation by a Montomorillonite Doped with Transition-Metal Cations" in Helvetica Chimica Acta, 70 (1987), p. 577. Here a process is disclosed for obtaining catalysts by the exchange of interstitial cations in the K-10 montmorillonite for use in alkylations with halides, alcohols and olefins. It was found that the efficiency of the catalyst bears no apparent relation to the corresponding Lewis acids under homogeneous conditions. Zirconium and titanium gave the best results in this study.
It would be a substantial advance in the art if phenol and acetone could be produced in yields approaching 100% by decomposition over an inexpensive catalyst using mild conditions. A catalyst which worked at very high space velocities using mild conditions and yet afforded high selectivities and yields with a smaller percentage of by-products would be particularly advantageous. Furthermore a very active, long life catalyst would also solve the catalyst disposal and acid entrainment problems referred to above.